微加工电化学沉积锌牺牲层工艺

在微加工中通过电化学沉积Zn制备牺牲层从而制备悬空结构。电化学沉积Zn牺牲层工艺具有易获取牺牲层,去除快速,腐蚀选择性好,耐高温等优点。在电化学沉积Zn牺牲层工艺中易遇到与基底结合力不够、使用高温工艺时易产生气泡、打磨后残留杂质、去除牺牲层时残留难去物和悬空结构释放时易黏附等问题,通过在Ti/Cu电镀种子层上预镀Ni薄层获使用Ti/Au电镀种子层、慢速升温的预真空高温烘烤、电解稀碱液法和氧化清洗、使用丙酮和F117进行应力释放等方法改进工艺后可以克服这些问题。电化学沉积Zn牺牲层工艺是较为理想的制备悬空结构的工艺。     

电化学沉积Cu牺牲层工艺用于制备面外运动电热微驱动器

用电化学沉积Cu作为牺牲层制备面外运动电热微驱动器的悬空结构,并建立了一种简单、可靠的牺牲层工艺技术.该工艺具有工艺流程简单、牺牲层易获取、释放简单、腐蚀选择性好、结构保存完整等优点.通过退火去除残余应力、使用丙酮和F113进行悬空结构释放等方法改进工艺,可以得到理想的器件.证明电化学沉积Cu是比较好的制备悬空结构的牺牲层工艺.     

一种MEMS复合牺牲层工艺的研究

以MEMS滤波器中的MEMS开关牺牲层的工艺为例,通过同时运用聚酰亚胺和正胶作为牺牲层材料的方法,避免了牺牲层单独使用聚酰亚胺做材料难于去除,或单独使用光刻胶做材料,叠层旋涂光刻胶时会出现龟裂的缺点.改善了牺牲层固化和刻蚀的效果,减小了刻蚀的时间.此研究应用在表面微细加工工艺中,对MEMS加工工艺具有一定的参考价值.     

基于光刻胶回流特性的平面化工艺

研究了一种利用光刻胶的回流特性去除表面的磨痕，使其表面平整化的方法，结合牺牲层结构可以非常简便地制备出微机电器件中各种悬臂梁结构。着重研究了光刻胶的前烘胶温度、回流温度、回流时间对回流效果的影响。通过大量的实验得到了较好的回流工艺，即光刻胶90℃下60min前烘后，并在90℃下回流60min，不但能通过机械抛光准确控制减薄厚度，而且还可以完全除去其表面的磨痕，获得平滑的表面结构。     

制备Cu互连悬空结构的新型工艺研究

为了降低集成电路中的互连延迟,采取了一种新型的集成电路Cu互连工艺,以掩膜电镀的方法制备Cu互连的叠层结构,借鉴MEMS工艺的牺牲层技术,用浓磷酸对Al2O3牺牲层进行湿法刻蚀,不仅在互连金属间介质层而且在层内介质层都形成了以空气为介质的Cu互连悬空结构.用一种叉指测试结构对以空气和聚酰亚胺为介质的互连性能进行了比较,结果表明,采用空气介质减小了互连线耦合电容,为进一步降低集成电路的互连延迟提供了途径.     

钠钙玻璃微流管道的厚胶湿法腐蚀工艺优化

为了克服石英玻璃和Pyrex 7740玻璃制作微流管道价格昂贵、工艺流程复杂等缺点,利用普通钠钙玻璃为基质、正光刻胶AZ4620为掩膜牺牲层,提出了一种高效、快速、低成本的微流管道制作方法.该方法优化了腐蚀工艺的关键参数,解决了光刻胶与玻璃的粘附性、光刻胶在腐蚀液中的耐受时间等问题.试验腐蚀深度达到80μm,最小特征尺寸小于50 μm,微流管道侧壁陡直度小于100°,底部平整度误差小于±1.5 μm,制作周期仅需4h左右.     

图形反转工艺用于金属层剥离的研究

研究了AZ-5214胶的正、负转型和形成适用于剥离技术的倒台面图形的工艺技术.用扫描电镜和台阶仪测试制作出的光刻胶断面呈倒台面,倾角约为60°,胶厚1.4μm.得到了优化的制作倒台面结构的光刻胶图形的工艺参数:匀胶转速4 000 r/min,前烘温度100 ℃,时间60 s,曝光时间0.3 s,反转烘温度110℃,时间90 s,泛曝光时间2 s,显影时间50 s.用金相显微镜测试了在优化工艺参数条件下制作的光刻胶图形的分辨率,同时对图形反转机理进行了讨论.     

间歇悬浮式厚胶显影工艺研究

介绍了一种间歇悬浮式厚胶显影工艺,采用该种显影工艺,对使用SU-8光刻胶进行涂胶,胶层厚度大于30μm的晶片进行显影。显影后的晶片进行电镀工艺,经过对显影后晶片上图形的观察和对电镀凸点的分析,证明该种显影工艺具有很好的效果。     

MEMS开关中聚合物牺牲层去除方法研究

制作了一种以聚酰亚胺作为牺牲层的低下拉电压开关,聚酰亚胺牺牲层采用反应离子刻蚀(RIE)工艺进行刻蚀。研究了刻蚀功率对刻蚀时间的影响,检验了不同刻蚀功率与刻蚀时间组合条件下开关梁的结构完整性,优化了该RIE工艺。实验结果表明,聚酰亚胺牺牲层的去除效果较好,其侧向刻蚀率为1.3 μm/min。最终获得了具有2 μm以下间隙、结构完整的MEMS开关梁。     

烘焙工艺条件对厚胶光刻面形的影响

采用厚层正性光刻胶AZ P4620进行光刻实验,考察了在前烘和坚膜阶段不同的工艺参数条件下的光刻胶浮雕面形的变化.实验表明,完全显影后光刻胶的浮雕面形受前烘工艺参数的影响很小,但其显影速率有一定差别;当坚膜烘焙后,不同前烘条件下的浮雕面形差别较大;当前烘条件相同时,坚膜参数的变化对光刻胶的浮雕面形影响较大.由此得出,在前烘阶段应采取较高温度、较短时间的烘焙,而在坚膜阶段应采取较低温度、较长时间的烘焙,这样可提高厚胶光刻面形的质量.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its